FKIE_CVE-2026-33693

Vulnerability from fkie_nvd - Published: 2026-03-27 01:16 - Updated: 2026-06-17 10:37
Severity
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Summary
Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the `v4_is_invalid()` function in `activitypub-federation-rust` (`src/utils.rs`) does not check for `Ipv4Addr::UNSPECIFIED` (0.0.0.0). An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the SSRF protection introduced by the fix for CVE-2025-25194 (GHSA-7723-35v7-qcxw), and reach localhost services on the target server. Version 0.7.0-beta.9 patches the issue.
References
security-advisories@github.comhttps://github.com/LemmyNet/activitypub-federation-rust/commit/4ae8532b17bc35755240b7f55d4a5b7665351599
security-advisories@github.comhttps://github.com/LemmyNet/lemmy/security/advisories/GHSA-q537-8fr5-cw35
security-advisories@github.comhttps://github.com/advisories/GHSA-7723-35v7-qcxw
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "lemmy",
          "vendor": "LemmyNet",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.7.0-beta.9"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the `v4_is_invalid()` function in `activitypub-federation-rust` (`src/utils.rs`) does not check for `Ipv4Addr::UNSPECIFIED` (0.0.0.0). An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the SSRF protection introduced by the fix for CVE-2025-25194 (GHSA-7723-35v7-qcxw), and reach localhost services on the target server. Version 0.7.0-beta.9 patches the issue."
    },
    {
      "lang": "es",
      "value": "Lemmy es un agregador de enlaces y un foro para el fediverso. Antes de la versi\u00f3n 0.7.0-beta.9, la funci\u00f3n `v4_is_invalid()` de `activitypub-federation-rust` (`src/utils.rs`) no comprueba si existe `Ipv4Addr::UNSPECIFIED` (0.0.0.0). Un atacante no autenticado que controle un dominio remoto puede apuntarlo a 0.0.0.0, eludir la protecci\u00f3n SSRF introducida por la correcci\u00f3n para CVE-2025-25194 (GHSA-7723-35v7-qcxw) y acceder a los servicios de localhost en el servidor de destino. La versi\u00f3n 0.7.0-beta.9 corrige el problema."
    }
  ],
  "id": "CVE-2026-33693",
  "lastModified": "2026-06-17T10:37:56.163",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 2.5,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-33693",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-03-30T11:50:59.456186Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-03-27T01:16:18.983",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/LemmyNet/activitypub-federation-rust/commit/4ae8532b17bc35755240b7f55d4a5b7665351599"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-q537-8fr5-cw35"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/advisories/GHSA-7723-35v7-qcxw"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-918"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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